Deep well motor impact tool and drilling apparatus



Oct. 15, 1968 c. J. CARR ETAL DEEP WELL MOTOR IMPACT TOOL AND DRILLINGAPPARATUS 7 w a 2 D, 0 M a. 4%4 7 rmw 224%. A 2,1 7 e l /27 Wm M A NQAVVZ 1. a F m mum m u J I a 2 w i 4 1 I ZWGN/ 1 MD A i g I 17/4 M D a Fa m M/ H wfwmw vfi w 0 C a p 1 United States Patent 3,405,771 DEEP WELLMOTOR IMPACT TOOL AND DRILLING APPARATUS Charles J. Can, Anaheim, andMarion Dudley Hughes, Long Beach, Calif. (both Mr. Dudley Hughes, 1111Security Bldg, Long Beach, Calif. 90362) Filed Apr. 12, 1966, Ser. No.542,159 11 Claims. (Cl. 175-73) ABSTRACT OF THE DISCLOSURE A combinationrotor and percussion deep well drilling tool including, an elongatevertical barrel with fluid conducting means at its upper end to connectwith a drill collar at the lower end of a drillin string, an elongate,tubular, fluid conducting column slidably engaged in the barrel andhaving a lower end depending therefrom, said column having means at itslower end to connect with a rotary bit, an elongate longitudinallyextending radially outwardly opening helical groove, and sealing meansat its upper end to seal between the column and the barrel, and drivemeans between the column and the barrel, and drive means between thebarrel and the column to rotate the column relative to the barrel upondownward shifting of the barrel relative to the column and including adrive sleeve adjacent the lower end of the barrel surrounding thecolumn, a cam lug on the sleeve and engaged in the groove, andreleasable clutch means between the barrel and the sleeve to establishdriving engagement between the sleeve and the barrel upon downwardshifting of the barrel relative to the column.

This invention has to do with an oil well tool and related apparatus andis more particularly concerned with a novel tool and apparatus adaptedfor use in directional well bore drilling operations. The art ofdrilling oil wells is old and highly developed. The art of directionaldrilling that is, the art of varying the direction in which a well boreis established, in a predetermined direction, is likewise highlydeveloped and well-known to those skilled in the art.

In the art of directional drilling, several basic methods are known andemployed. The most widely used method of changing the direction in whicha well bore is being established is to arrange a wedge member in thebottom of a bore hole, in predetermined rotative position, which memberserves to urge and direct the bit at the lower end of a string of drillpipe, laterally from its previous course. Such wedges are commonlyreferred to as whipstocks.

Another method of directional drilling i to provide a special tool inthe lower end of a drilling string to engage the adjacent wall of thewell bore and to urge the string, and its related bit, laterally in anew and desired direction.

Yet another method of directional drilling, referred to as spudding,involves the use of a special bit at the lower end of drill pipe string,which hit directs a fluid jet in the direction in which it is desired toestablish new holes. The bit is reciprocated vertically adjacent thebottom of the well bore so that the fluid jet acts on and reduces, orwashes away, the formation at one side of the bore hole. When theformation is sufliciently washed away or reduced by the action of thejet, the bit, in principal, is permitted to shift laterally and thedirection of subsequently drilling or new hole is deflected relative tothe hold or established previously established hole.

In the case of whipstock, and in those methods where special tools areengaged in the drilling string to urge them laterally in the bore holes,conventional rotary bits and rotary drilling methods are employed. Thatis, the

3,405,771 Patented Oct. 15, 1968 bits are rotated and advanced into theformation to establish new hole and the drilling strings are turned andtorqued to a considerable extent.

The above-noted turning and torquing of the drilling string, whencarrying out directional drilling operations, tends to and frequentlydoes upset and alter the setting of the means employed to effectreflection of the bit and also tends to and frequently does cause thebit to drift ofl the desired course. Unfortunately, it is not untilafter such undesired deviation in direction is an accomplished fact,that it is discoverable and considerable time and expense is required tocorrect it.

In carrying out directional drilling operations with whipstocks, theangle or extent to which the bit and drilling string can be deflected isextremely limited and frequently requires several runs to achieve thedesired deflection. That is, a number of Whipstocks must be set, in aseries, as the well bore is advanced into the formation to achieve thedesired deflection. Such a procedure necessarily requires a plurality oftime-consuming and costly operations, any one or more of which might, aspointed out above, be ineffective and costly to correct.

The above-noted spudding method of directional drilling is onlyeflfective in those situations where the forrnation is sufiiciently softand unstable to be effectively reduced by fluid jets. Accordingly,spudding is only employed in shallow wells where relatively softformations are encountered.

Another special and effective method of directional drilling involvesthe provision of a hydraulic motor engageable in a drilling stringbetween a rotary bit and a drill collar, immediately above the bit. Themotor turns the bit relative to the drill string. With such a set-up itis possible to urge the lower end of the drilling string laterally withany desired or suitable oriented means and to then rotate the bit andadvance the bit and the string so as to effect desired deflection of thewell bore. While this rather special set-up overcomes many shortcomingsfound in the use of other available tools, and apparatus for directionaldrilling operations, it has been proved to be critically wanting in thatthe fluid motors are extremely costly to build, service and maintain andsuch motors are not suitably dependable.

An object of our invention is to provide a novel motor tool engageablebetween a drill string and rotary bit, which tool is such that itconverts reciprocating motion to rotary motion and is effective torotate the bit upon reciprocation of the drilling string.

Further, it is an object of our invention to provide a tool of thecharacter referred to which is such that rotary motion of the drillingstring can be directly transmitted through the tool to the bit, if suchis desired.

Still further, it is an object of our invention to provide a tool of thecharacter referred to which is such that it can act as a knocker, whileconverting axial or reciprocating motion to rotary motion and to therebypermit or allow for a combination of rotary and percussion drillingtechniques.

Yet another object of our invention is to provide a tool of thecharacter referred to and related apparatus, which permits reciprocationof the drilling string with resulting rotation of the bit and, ifdesired, knocking of the bit, without requiring the bit to be elevatedor raised from engagement with the bottom of the established bore hole.

A further object of the invention is to provide an apparatus fordrilling a well hole including a motor tool of the character referredto, a bit carried and driven by the motor tool, a string of drillcollars of predetermined mass above and connected with the motor tooland an axially shiftable lost motion sub-tool at the upper end of thedrill collars, whereby the axial and the torsional V 3 forces exertedonto and through the motor tool and bit can be accurately controlled.

It is yet another object of our invention to provide an apparatus of thecharacter referred to above which includes an elbow or angle sub in thedrilling string in or above the drill collars, which elbow sub can bearranged in any desired rotative position and causes the drilling stringto bear on opposite sides of the well bore, or the casing therein,and'disposes the drill collars, motor tool and bit at a predeterminedangle from the'longitudinal axis of the established bore hole.

' A further object of this invention is'to provide a motor tool of thecharacter referred to which is easy and economical to manufacture,service and maintain and a tool which is rugged, durable and highlyeffective and dependable in operation.

An object of our invention is to provide an apparatus of the characterreferred to which is easy and economical to manufacture, assemble,service and maintain, which is easy, convenient and accurate ineffectively deflecting a well bore and'which is rugged and dependable inoperation.

These and other objects and features of our invention will be fullyunderstood from the following detailed description of a typical form andapplication of our invention, throughout which description reference ismade to the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view of a well structure with theapparatus that we provide arranged therein;

FIG. 2 is a sectional view of our new motor tool, taken substantially asindicated by line 22 on FIG. 1;

FIG. 3 is an enlarged detailed sectional view taken substantially asindicated by line 33 on FIG. 2, having parts removed to betterillustrate the details of the construction;

FIG. 4 is a sectional view taken substantially as indicated by line 4-4on FIG. 3, without parts removed and showing the parts in anotherposition; and,

FIG. 5 is an isometric view of the loss motion sub such as is employedin our new apparatus.

The motor tool A that we provide includes an elongate vertical tubularbarrel B with a downwardly opening, longitudinally extending cylindricalbore 10, a head 11 at the upper end of the barrel defining a downwardlydisposed stop shoulder 12 adjacent the upper end of the bore and havinga tool joint member at its upper end to cooperate with a mating tooljoint member on a related tool or drill collar.

In the case illustrated, the tool joint member on the head is shown asan upwardly projecting threaded pin 14 and is shown engaged in athreaded box 15 in the lower end of the related drill collar 16.

The head is further provided with a central flow passage 17 tocommunicate with and conduct circulating fluid between the flow passage18 in the drill collar 16 and the bore 10 of the barrel B.

The lower end of the barrel B is povided with or carries a releasabledrive means P, which drive means will be fully described in thefollowing.

The motor tool A, in addition to the barrel B and releasable drive meansF, includes a driven column C.

The column C includes an elongate vertically extending cylindricalmember 20, which member is slightly longer in longitudinal extent thanthe bore 10 in the barrel .B and which is slidably engaged in said boreto depend from the lower end of the barrel.

The member 20 of the column C is provided at its upper end with thebumper head 21 having a flat top surface 22 to oppose and engage thestop shoulder or surface 12 of the barrel head 11.

The head 21 is provided with suitable sealing means s to seal betweenthe bore 10 of the barrel and the upper end of the column. In the caseillustrated, the means S is shown as involving a pair of radiallyoutwardly opening, axially spaced, grooves 23 and O-ring seals 23 in thegrooves and engaging the barrel bore 10. i

The lower end of the driven column C is provided with an enlargement 24defining a tool joint to connect the column with a related tool, such asa rotary bit E.

The tool joint on or in the enlargement 24 is shown as a threaded box 25in which a threaded pin 26 on the bit E is engaged.

The driven column C is provided with a central longitudinal flow passage27 communicating with and adapted to conduct circulating fiuid betweenthe bore 10 in the barrel and a fluid passage 28 in the bit E, whichpassage 28 conducts fluid to suitable nozzles in the bit construction,in accordance with common practice, 7

Finally, the member 20 of the driven column C is pro vided with at leastone, but preferably-two or more, radially outwardly opening helicalgrooves 30 having radially outwardly disposed bottoms 31, radiallyoutwardly extending, downwardly and circumferentially disposed upperdrive surface or inclined planes 32 and radially outwardly, upwardly andcircumferentially disposed lower surfaces or inclined planes 33.

The reversible drive means F includes a drive sleeve 40 slidably engagedabout the member 20, below the barrel B, radially inwardly projectingcam lugs '41 carried by the sleeve 40 and slidably engaged in thegrooves 30, clutch means G between the barrel and the sleeve andreleasably establishing driving engagement between the barrel and thesleeve. The clutch means G is a simple, jaw-type clutch and includes aplurality of circumferentially spaced, teeth 42 on and about the lowerend of the barrel B and a plurality of circumferentially spaced teeth 43on and about the upper end of the sleeve 40 and opposing and adapted tomate with the teeth 42.

By shifting the sleeves 40 downwardly relative to the barrel a distanceslightly greater than the depth of the teeth, the clutch means isdisengaged and the sleeve is free to rotate relative to the barrel. Uponshifting the sleeve upwardly relative to the barrel, or shifting thebarrel down-wardly relative to the sleeve, the clutch means is engagedand positive driving engagement is established between the barrel andthe sleeve.

The drive means further includes a tubular cage 45 threaded on the lowerend of the barrel, as at 46 and depending therefrom to surround or occurabout the sleeve 40 with running clearance. The cage 45 depends belowthe lower end of the sleeve and is provided with a radially inwardlyprojecting retaining flange 47 on which an anti-friction bearing 48 isseated.

The bearing 48 rotatably supports the sleeve 40 when the sleeve isshifting downwardly relative to the barrel and when the clutch means isdisengage-d.

In operation, when the barrel is shifted upwardly relative to the drivencolumn, as by elevating the drill collars 16 and the elements or partsof the drilling string occurring above the collars, the sleeve, by itsweight and by the frictional drag between the cam lugs 41 and thegrooves 30, is shifted downwardly into supported engagement on thebearing 48 and the clutch means is disengaged. Upon further upwardshifting of the barrel relative to the column C, the lugs follow thegrooves and the sleeve rotates freely until the cam lugs reach and stopat the upper end of the grooves.

Note, that when the barrel is shifted upwardly, the cam lugs ride on thelower inclined planes or surfaces 33 of the grooves.

Upon subsequent downward shifting of the barrel B relative to the columnC the sleeve 40 is, by virtue of the frictional resistance between thesleeve and the column and the cam lugs and the grooves, shifted upwardlyso that the clutch means is engaged and driving engagement isestablished between the barrel and the sleeve.

Upon subsequent downward shifting of the barreland sleeve, the lugscarried by the sleeve bear against the upper inclined planes or surfaces32 of the grooves and rotate the column and the bit E related thereto,relative to the barrel.

Accordingly, by reciprocating the drilling string above the tool A, thebit E can be intermittently rotated without rotating the drillingstring.

By lowering the barrel to its lowermost position, the shoulder orsurface 12 of the barrel head strikes the top surface of the knockerhead on the column C and an impact is transmitted through the tool andbit, to the formation, to effect percussion reduction of the formation.

It is extremely important to note that the bit E is not elevated fromengagement on the bottom of the established bore hole during operationof our construction.

By varying the longitudinal extent of the barrel and column and byvarying the pitch of the grooves, the number of revolutions of the bit,upon each stroke or downward shifting of the barrel, relative to thecolumn, can be advantageously controlled.

By reducing the pitch of the grooves, a greater number of revolutionsper stroke can be gained, and a greater amount of axial force isrequired to effect operation of the motor.

The increase in force required to operate the motor also increases thedirect axial force or weight applied onto and through the bit E.Accordingly, the force exerted onto and through the bit can becontrolled.

It will be apparent that as the pitch is varied to control the weightapplied to the bit and the weight force required to effect operation ofthe tool is varied, the weight force required for satisfactory operationcan be controlled from the top of the well or can be controlled at thebottom of the well by varying the amount and mass of heavy drill collaror collars provided immediately above the tool.

In practice, and as illustrated, the pitch of the upper end portions ofthe grooves can be increased to be substantially parallel with the axisof the construction so that upon initial downward movement of thebarrel, an extremely high-weight torque ratio is provided to ini tiateor start rotation of the column and bit. Once such rotation is started,less force is required to continue rotation and greater axial force canbe transmitted through the construction. Accordingly, the pitch of thegrooves can, as shown, decrease as they continue downwardly toefiectively increase the number of revolutions and to increase the axialforce applied by the bit onto the formation.

It is to be noted that since the cam lugs 41 are greater in longitudinalextent than the Width of the grooves and since the said lugs are fixedand integrally formed on the sleeve, the high pitched upper portions ofthe grooves 30 are made wider or greater in width than their low pitchedlower portions, to accommodate the lugs.

It will be apparent that fluid pressure acting upon the top of thecolumn C, within the barrel, holds the column and bit downwardly and incontact with the bottom of the bore hole upon upward shifting of thebarrel.

'Suflicient weight on the downstroke, overcomes the effect of the fluidacting upon the top of the colunm so that no fluid locking action, whichwould impede operation of this tool, will occur.

In practice, a bi-pass port 60 can be provided between the flow passagein the column and the upper end of each groove to conduct clean drillingfluid into the grooves.

Such drilling fluid acts as a lubricant and also flushes out anycuttings, and the like, that might otherwise migrate into the groovesand foul operation of the construction.

Also, ports 61 and 62 can be provided in the cage adjacent the clutchmeans and adjacent the bearing 48, through which mud and like, whichmight otherwise accumulate in the clutch means and between the sleeveand the bearing, can be displaced as the construction is operated.

The apparatus for directional drilling that we provide, which isillustrated in FIG. 1 of the drawings and which includes our new motortool, involves the bit E, the motor tool A connected with and extendingupwardly from the bit, a length or stand of drill collars 16 fixed toand extending above the tool A, an elbow :or angle sub H fixed to theupper end of the collars 16, an axially extensible or low lost motionsub I fixed to the upper end of the sub H; a string of drill pipe Pextending from the sub I to the top of the well and an elevator J -atthe upper end of the string P and connected with a suitable circulatinghose K.

The elbow or angle sub H is a simple short sub with the axes of itsupper and lower ends disposed at an angle of from three degrees to tendegrees.

The lost motion sub I is a simple bumper sub type of constructioncapable of equal or greater axial movement than the tool A.

In FIG. 5 of the drawings, we have illustrated a typical bumper sub typeconstruction as might be advantageously employed in carrying out ourinvention. Since the exact construction of the sub I can vary widelywithout aliecting or altering the invention, and since suchconstructions are well known to those skilled in the art, detaileddescription of the sub I will be dispensed with.

When the drilling string assembly illustrated in FIG. 1 of the drawingsis lowered into the well, the elbow sub H creates a bend in the stringwhich causes that sub to bear on one side of the well bore and whichcauses those portions of the string occurring above and below that sub,to bear on diametrically opposite sides of the well bore.

Accordingly, the portion of the string occurring below the sub H, thatis, the drill collars 16, tool A and bit E, are on a common axisangularly related to those portions of the drilling string occurringabove the sub H and angularly related to the longitudinal axis of theestablished well bore.

Since the rotative position of the sub H is known and tfixed, it ispossible, by employing any convenient means of orientation, to orientthe sub H and the portion of the string therebelow so that the saidportion of the string occurring below the sub H and particularly the bitE, are disposed in predetenmined angular relationship to the axis of theWell bore.

Upon orienting the drilling string in the manner set forth above, thedrill pipe P is elevated and the sub I is extended fully. Uponsubsequent elevation of the drill pipe string P, the lower portion ofthe string is elevated and the tool A is extended (the bit remaining onbottom).

When the tool is fully extended the drill pipe string is lowered,collapsing or shortening the sub I and permitting the weight of thestructure therebelow to actuate the tool A.

At this point it should be noted that the sub I prevents application ofexcessive weight on the tool A and permits the portion of the stringbelow the sub I to be operated independently of the weight and efiect ofthe drill pipe string above the sub. This is highly important, asrapidly lowering and applying the weight of the pipe string above thesub onto and through the remainder of the construction would tend tocause twisting and collapsing of the string in such a manner as to upsetorientation of the structure.

After the tool A is actuated or cycled, as set forth above, the string Pcan again be elevated and the structure re-cycled, as desired.

It will be apparent that the new hole established will be angularlydisposed to the old or previously established hole and that uponcontinued operation of the apparatus, and the establishment of new hole,the angle of the new hole will progressively change angle, as desired,with the result that any desired amount of deflection can be establishedwith a single run of our new tool and apparatus.

It is to be noted that when the tool A has been actuated and bottomedout, that is, when the barrel has reached its lowermost position and thesub I is bottomed out, that is, when it is in its collapsed orcompletely shortened position, the entire weight of the string can beapplied to and through the bit and the string can be rotated and newhole established in a conventional manner. In this situation, the sub Iand tool A become inoperative.

It will also be apparent that when the tool A is bottomed out andinoperative, as set forth above, the string can be rotated in aconventional manner even though the sub I is not bottomed out. In thissituation, the weight applied onto and through the bit is limited to theweight of that portion of the string occurring between the bit and thesub.

If conventional rotary drilling operations are carried out andsuflicient resistance is afforded by the bit to cause the barrel of thetool A to rotate about the column C and thereby cause the lugs 41 toride up in the grooves 30 and to thereby extend the tool A, suchextending and resulting jacking up of the string will stop when the lugsreach the upper ends of the grooves and the operation can be continuedwithout further or adverse effect.

Having described only a typical preferred form and application of ourinvention, we do not wish to be limited to the specific details hereinset forth, but wish to reserve to ourselves any modifications and/ orvariations that may appear to those skilled in the art and which fallwithin the scope of the following claims:

Having described our invention, we claim:

1. A deep well motor tool of the character referred to including, anelongate vertical barrel with fluid conducting means at its upper end toconnect with a part in a drilling string, an elongate, tubular, fluidconducting column slidably engaged in the barrel and having a lower enddepending therefrom, said column having means at its lower end toconnect with a part in a drilling string, an elongate longitudinallyextending radially outwardly opening helical groove, and sealing meansat its upper end to seal between the column and the barrel, and drivemeans between the barrel and the column to rotate the column relative tothe barrel upon downward shifting of the barrel relative to the column,said drive means including a drive sleeve adjacent the lower end of thebarrel surrounding the column, a cam lug on the sleeve and engaged inthe groove, and releasable clutch means between the barrel and thesleeve to establish driving engagement between the sleeve and the barrelupon downward shifting of the barrel relative to the column.

2. A structure as set forth in claim 1 wherein, said sleeve is carriedby the barrel for limited axial shifting relative thereto and saidclutch means include a plurality of circumferentially spaced, depending,jaw teeth at the lower end of the barrel and a plurality ofcircumferentially spaced, upwardly projecting jaw teeth at the upper endof the sleeve and shiftable into and out of engagement with saiddepending teeth.

3. A structure as set forth in claim 1 wherein, the upper end of thebarrel is provided with a downwardly disposed stop surface and the upperend of the column is provided with a knocker head adapted to be engagedby the stop surface.

4. A structure as set forth in claim 1 wherein, said sleeve is carriedby the barrel for limited axial shifting relative thereto and saidclutch means include a plurality of circumferentially spaced, dependingjaw teeth at the lower end of the barrel and a plurality ofcircumferentially spaced, upwardly projecting jaw teeth at the upper endof the sleeve and shiftable into and out of engagement with saiddepending teeth, the upper end of the barrel being provided with adownwardly disposed stop surface and the upper end of the columnprovided with a knocker head adapted to be engaged by the stop surface.

5. A structure as set forth in claim 1 wherein, the pitch of the grooveis increased at its upper end and terminates to establish a stop againstwhich the lug stops to limit downward movement of the column relative tothe barrel.

6. A structure as set forth in claim 1 wherein, said sleeve is carriedby the barrel for limited axial shifting relative thereto and saidclutch means including. a plurality of circumferentially spaced,depending jaw teeth at the lower end of the barrel and a plurality ofcircumferentially spaced, upwardly projecting jaw teeth at the upper endof the sleeve and shiftable into and out of engagement with saiddepending teeth, the upper end of the barrel being provided with adownwardly'disposed stop surface and the upper end of the columnprovided with a knocker head adapted to be engaged by the stop surface,the pitch of the groove being increased at its upper end and terminatingto establish a stop against which the lug stops to limit downwardmovement of the column relative to the barrel.

' 7. A structure as set forth in claim 1 wherein, said sleeve is carriedfor free rotation and limited axial shifting by a cage fixed to anddepending from the lower end of the barrel and carrying a bearing uponwhich the lower end of the sleeve can seat, said clutch means includingfixed jaws at the upper end of the cage and jaws at the upper end of thesleeve, and adapted to be shifted into and out of engagement with thefixed jaws upon reltive axial shifting of the barrel and column.

8. A structure as set forth in claim 1 wherein, said sleeve is carriedfor free rotation and limited axial shifting by a cage fixed to anddepending from the lower end of the barrel and carrying a bearing uponwhich the lower end of the sleeve can seat, said clutch means includingfixed jaws at the upper end of the cage and jaws at the upper end of thesleeve, and adapted to be shifted into and out of engagement with thefixed jaws upon relative axial shifting of the barrel and column, theupper end of the barrel is provided with a downwardly disposed stopsurface and the upper end of the column is provided with a knocker headadapted to be engaged by the stop surface, said column having a centrallongitudinal flow passage, a by-pa-ss port establishing communicationbetween the flow passage and the upper end of the groove to conductfluid from within the column into the groove.

9. A structure as set forth in claim 1 wherein, said sleeve is carriedfor free rotation and limited axial shifting by a cage fixed to anddepending from the lower end of the barrel and carrying a bearing uponwhich the lower end of the sleeve can seat, said clutch means includingfixed jaws at the upper end of the cage and jaws at the upper end of thesleeve, and adapted to be shifted into and out of engagement with thefixed jaw upon relative axial shifting of the barrel and column, theupper end of the barrel is provided with a downwardly disposed stopsurface and the upper end of the column is provided with a knocker headadapted to be engaged by and the stop surface, said column having acentral longitudinal flow passage, a by-pass port establishingcommunication between the fiow passage and the upper end of the grooveto conduct fluid from within the column into the groove, and radiallyoutwardly opening ports in the cage adjacent the clutch and adjacent thebearing to exhaust matter from between the jaws of the clutch andbetween the bearing and the sleeve when said sleeve is shifted axiallyin the cage.

10. A structure as set forth in claim 1 wherein, said sleeve is carriedfor free rotation and limited axial shifting by a cage fixed to anddepending from the lower end of the barrel and carrying a bearing uponwhich the lower end of the sleeve can seat, said clutch means includingfixed jaws at the upper end of the cage and jaws at the upper end of thesleeve, and adapted to be shifted into and out of engagement with thefixed jaws upon relative axial shifting of the barrel and column, theupper end of the barrel is provided with a downwardly disposed stopsurface and the upper end of the column is provided with a knocker headadapted to be engaged by the stop surface, said column having a centrallongitudinal flow passage, 21 by-pass port establishing communicationbe-- tween the fiow passage and the upper end of the groove to conductfluid from within the column into the groove,

and radially outwardly opening ports in the case adjacent the clutch andadjacent the bearing to exhaust matter from between the jaws of theclutch and between the bearing and the sleeve when said sleeve isshifted axially in the cage, the pitch of the groove being increased atits upper end and terminating to establish a stop against which the lugstops to limit downward movement of the column relative to the barrel.

11. A directional drilling apparatus including, a rotary bit, a motortool fixed to and extending upwardly from the bit, a string of drillcollars fixed to and extending upwardly from the motor tool, an elbowsub fixed to the upper end of the drill collar string, an axiallyshiftable lost motion sub fixed to and extending upwardly from the elbowsub, a drill pipe string fixed to and extending upwardly from the lostmotion sub, and an elevator at the upper end of the drill pipe string,said motor tool including an elongate barrel fixed to and depending fromthe lower end of the drill collar string, a column with a helical groovefixed to and projecting upwardly from the bit and slidably engaged inthe barrel, a drive sleeve rotatably carried by the lower end of thebarrel for limited axial movement and free relative rotation and havinga radially inwardly projecting cam lug slidably engaged in the groove,and clutch means between the sleeve and the barrel to establish drivingengagement between the barrel and the sleeve when the barrel is shifteddownwardly relative to the column and the sleeve and to break saiddriving engagement when the barrel is shifted upwardly relative to thecolumn, said apparatus adapted to be engaged in a well hole with saidelevator at the top of the hole, the bit engaged on the bottom of thehole, and the elbow sub engaging one side of the hole above the bottomthereof whereby the axes of the strings of drill collar and drill pipeare angularly related to the axis of the hole, said elevator drill pipestring and lost motion sub being adapted to be intermittently elevated"to intermittently elevate the elbow sub, drill collar string and motortool barrel relative to the motor tool column and the bit and beingadapted to be intermittently lowered whereby the elbow sub, drill collarstring and motor tool barrel are free to shift downwardly relative tothe motor tool column to apply their weight onto and through the bit andto rotate the bit.

References Cited UNITED STATES PATENTS 2,002,385 5/1935 Bannister 1751062,002,386 5/1935 Bannister 175-106 X 2,013,070 9/1935 Sheridan 175-106 X2,287,157 6/1942 Wolfi 175-106 NILE C. BYERS, 111., Primary Examiner.

